A photocatalyst has a high capacity of oxidizing and decomposing, for example, organic matters or apart of inorganic substances such as NOx. And, the light which is available at low cost and has a small environmental load may be used as an energy source. Therefore, in recent years, the application of the photocatalyst to environmental clean-up, deodorization, antifouling, and sterilization has been advanced, and various photocatalysts have been developed and studied.
Among them, the photocatalyst material responsive to visible light is expected, and thus, the study and development thereof have been progressed.
For example, Patent document 1 discloses a photocatalyst responsive to visible light in which a halogenated platinum compound (0.01 to 1% by weight, calculated based on platinum) is supported on the surface of catalyst particles such as titanium oxide.
Patent document 1: Japanese Patent Application Laid-Open No. 2004-73910.